San Diego  Trius Therapeutics reported a net loss of $14.2 million, or 36 cents per share, in the fourth quarter ended Dec. 31. In the same quarter a year earlier, the San Diego biotech company lost $12.5 million, or 44 cents per share. The number of shares outstanding increased to 39.6 million from 28.6 million during that time.

During the full year 2012, Trius lost $53.9 million, or $1.42 cents per share, compared with a loss of $18.3 million, or 69 cents per share, for the previous year.

Revenue for the quarter was $5.2 million, compared with $5 million in the year-ago quarter. For the year, Trius reported revenue of $27.2 million, compared with $41 million in 2011. Trius said revenue was higher in 2011 because it received a $25 million one-time payment from its partner Bayer Pharma AG. Bayer is helping Trius develop its flagship antibiotic, tedizolid phosphate.

The antibiotic treats "superbug" infections, such as MRSA, or methicillin-resistant Staphylococcus aureus.

Trius increased research and development expenses to $69 million in 2012 from $49.5 million in the previous year. The increase is due to development of tedizolid, Trius said.

Trius plans to file for marketing approval for tedizolid later this year, said Jeffrey Stein, Trius president and CEO. The company intends to sell tedizolid for acute bacterial skin and skin structure infections.

The company said it plans to begin a Phase 3 trial of tedizolid for pneumonia in the second half of the year. Next year, Trius plans to start a Phase 1 trial of another drug to fight gram-negative and gram-positive bacteria.

Trius ended the year with $66 million in cash and equivalents. In January, the company raised $31.6 million from a stock offering.